1. Technical Field
The present invention relates to a fluid-containing apparatus for washing foreign matter, such as dirt, from produce, such as potatoes and the like, after the produce has been harvested.
2. Description of Related Art
Agricultural produce, such as potatoes, requires washing after harvest and prior to further processing or packaging. Washing produce, particularly potatoes, requires careful handling, because the produce is quite delicate and subject to bruising. Various types of washing devices have been used to wash potatoes after harvesting. Sometimes the potatoes are washed by spray nozzles as the potatoes are conveyed down a line. Absent sufficient pre-soaking, spraying with nozzles alone fails to efficiently remove dirt, especially dirt embedded in the eyes of the potatoes. Consequently, much greater amounts of water must be used and far more nozzles are required without sufficient pre-soaking. To overcome this deficiency, previous systems have used large, permanent structures filled with water with some type of agitating device to provide a pre-soak wash prior to spraying. Such structures are expensive, and require intense maintenance to remove the dirt and rocks that accumulate on the bottom. Further, such systems are not typically “first in first out,” meaning that the potatoes randomly enter and exit the pre-soaker. Additionally, the agitating device is subject to routine failure because of the rock and dirt environment it is subject to. Consequently, such systems fail to efficiently and continuously remove both rocks and floating debris. Accordingly, a need exists for an improved apparatus and method for washing produce, such as harvested potatoes, in a more efficient manner.
One solution to washing produce is exemplified by U.S. Pat. No. 5,413,131 (“the '131 patent”) which discloses a washer for buoyant produce, such as radishes. The '131 patent discloses a wash tank having baffles placed across the entire width of the tank. The baffles are oriented as alternating from being mounted to the floor of the tank extending upward and mounted from the top of the tank and extending downward, below the water level. The baffles are thereby offset from one another along the internal length of the tank so that essentially every other baffle is an upper baffle and in between each of the upper baffles is a lower baffle. The nozzles are directed in a downward position and the spray discharge produces a strong, downward current that forces buoyant produce completely under water so the produce can move underneath the upper baffles. The buoyant produce then floats up and over the lower baffle before being again subjected to a strong, downward current from another set of spray nozzles.
There are several problems with this type of prior art washer. First, the water from the spray nozzles fails to directly contact the produce. In fact, because the produce is forced under water, there is a low statistical chance for the spray to directly engage the outer periphery of the produce and the standing water actually protects dirt on the produce from the spray. Consequently, it fails to address the issue of removing dirt embedded in produce including the removal of dirt from the eye of a potato. Because the sprays function like eductors to move the produce through the washer, the prior art washer disclosed in the '131 patent is very energy inefficient.
Another problem with this prior art washer is that it fails to work well for heavier than water produce, such as potatoes. While the density of the fluid could be adjusted to increase the relative buoyancy of the potatoes, this is an additional expense, and the additive could impart undesirable flavor components to the potato. Further, such adjustment can introduce waste disposal issues. The washer in the '131 patent also requires an extensive and complex array of nozzles which must be manually adjusted prior to start up. Consequently, a need exists for an improved produce washer that is capable of efficiently washing buoyant or non-buoyant produce, such washer should minimize the amount of water consumed, and also minimize the number of moving parts required.